Note from asker: I am an Android Developer and the maps in our app are currently not accessible by screen readers, and we'd love to improve this.
Jason: I have not tested mobile-native applications. Our web applications are responsive and have been tested on Chrome, Firefox, and Edge browsers. I do not have the hardware or software to test our web applications on mobile devices. (We do use device simulation software for testing.)
Lolly: I do not find maps on mobile apps very helpful. It could be the small screen or just that I haven't understood what the developer is trying to communicate. They are confusing to me. Maps in general are not easy to understand conceptually, so having a larger space to make sense of the data sometimes helps as does getting good spatial location clues. I prefer a 3-D experience.